The invention refers to a compressor system, especially for transporting gases or gas/oil mixtures in the offshore area. The compressor system has a seawater-proof housing with at least one entry opening for gases or gas/oil mixtures which are to be compressed and with at least one discharge opening for the compressed gases or gas/oil mixtures. It has a compressor which is arranged in the housing and which on the inlet side is connected to the entry opening and on the outlet side is connected to the discharge opening. An electric motor is arranged in the housing, with a stator packet and a rotor packet for driving the compressor.
Offshore transporting, that is to say the transporting of oil and gas in coastal waters, makes high demands on compressor systems. They must stand up to harsh climate, corrosive environmental conditions and also to unpredictable gas compositions. The compressor systems can be driven by an electric motor or by a gas turbine. The electric motor is preferably a brushless asynchronous motor. For compressing, a high-speed turbine is customarily used, wherein in this case the turbine and the electric motor are preferably arranged on a common shaft. The brushless and gearless drive allows an almost maintenance-free operation of such compressor systems. Alternatively, screw compressors or piston compressors can also be used for compressing.
The considered compressor systems can be installed in petrochemical facilities on the coast, on drilling platforms or even under water. In the last case, driving the compressor is typically carried out by an electric motor.
Supplying of the gas or of the gas/oil mixture is customarily carried out via a pipeline which is flanged on the housing outer side of the compressor system. In a corresponding manner, the further transporting of the compressed gas or gas/oil mixture on the outlet side is carried out via a further pipeline. Alternatively, a pressure hose can be used instead of a pipeline.
The high electrical connected load of the electric motors which are used in the region of more than 100 kW necessitates cooling of the electric motors. An oil cooling system, which as a separate unit is connected to the compressor system via oil feed lines and oil return lines, is customarily used. Such compressor systems are disadvantageously extensive on account of the externally arranged oil cooling systems.
A further disadvantage is that the external oil cooling systems can become unsealed with time. For one thing, the oil feed lines and the oil return lines themselves can become unsealed, especially as a result of seawater-induced corrosion or as a result of mechanical actions, such as a result of the dashing of waves. For another thing, connections, which are constructed in a pressure-tight manner, of the pipelines on the housing of the compressor system can also become unsealed with time. Escaping oil and also oil/gas mixtures constitute a potential ecological hazard for the surrounding water in this connection.